1. Field of Invention
The present invention relates to folding furniture, and more particularly to a foldable frame which is adapted for selectively adjusting the extension of the foldable frame so as to regulate the tension of the supporting fabric.
2. Description of Related Arts
Referring to FIG. 1, a conventional foldable frame for supporting a fabric thereon, such as foldable table or foldable leg rest supporting frame, is constructed by metal tubes wherein the foldable frame comprises a plurality of construction tubes pivotally connected together wherein they cross so that the foldable frame can be easily unfolded to provide a rigid cross-support for use and be folded up for storage.
Because such a conventional foldable frame can be quickly and easily unfolded for use and folded into a compact unit for carriage, a user can carry the foldable frame such as foldable table to everywhere such as campground or beach. However, when the user puts an object on the fabric which is supported by the foldable frame, due to the weight of the object, the tension of the fabric is not stretched enough to well support the object thereon. This causes the fabric to be distorted and misshapen so as to provide an unbalanced supporting surface of the fabric.
In other words, the stress on the fabric has simply been transferred to a downward pulling force on the fabric. As a result, the foldable frame tends to fold up and the object will not be substantially supported on the fabric. So, the foldable frame fails to well support the object on the fabric.
A main object of the present invention is to provide a foldable frame for supporting a fabric thereon wherein the foldable frame can well support a downward pulling force applied on the fabric in such a stable manner.
Another object of present invention is to provide a foldable frame which can substantially increase the tension of the fabric to distribute and support the downward pulling force and stress.
Another object of the present invention is to provide a foldable frame which is adapted for selectively adjusting the tension of the fabric to enhance an object on the fabric in a state of balance.
Another object of the present invention is to provide a foldable frame which has a simple construction that every individual is able to fold and unfold the foldable frame in one single motion.
Another object of the present invention is to provide a foldable frame which is adapted for being folded into a compact unit for easily storage and carriage.
Accordingly, in order to accomplish the above objects, the present invention provides a foldable frame for supporting a fabric thereon, comprising:
at least three pairs of frame legs each of which comprises a pair of first and second frame legs pivotally connected together where the first and second frame legs cross;
an upper frame joint for pivotally connecting top ends of the first frame legs;
a lower frame joint for pivotally connecting lower ends of the second frame legs wherein the lower frame joint is positioned below and aligning with the upper frame; and
a coupling joint slidably connected between the upper frame joint and the lower frame joint for selectively adjusting a vertical distance therebetween, so as to regulate a tension of the fabric.